JP2009217539A - Input data filtering method, and input data filtering apparatus to be used for implementing the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably and quickly determining ON/OFF by filtering input data. <P>SOLUTION: This method samples input data in timing of a shorter period than the state time width of the input data and determines the data when the same sampling value are continuously obtained a specified number of times or more. At least one of sampling timing and the specified number of times can be set arbitrarily. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a filter method that enables input data to be determined early by suppressing the influence of disturbance noise and the like, and an input data filter device that is used to implement the method.

  A programmable controller is used as a control device for factory automation (FA) installed in a production factory or the like. This programmable controller includes a building block type composed of a plurality of modules. As the plurality of modules, there are a power supply module, a CPU module, an input module, an output module, a communication module, and the like. The CPU module includes a CPU, an I / O memory, a program memory, and the like, and this CPU performs an IN refresh process for fetching a signal input from the input module into the I / O memory, and stores the sequence program in the program memory. Performs an operation based on the result, writes the result of the operation to the I / O memory and sends it to the output module, performs an OUT refresh process, and then transmits / receives data to / from another PLC on the communication network via the communication module. A series of processing for performing peripheral processing such as data transmission / reception to / from an external PC or the like via a communication port provided in is cyclically repeated (see, for example, Patent Document 1). An input device such as a sensor is connected to the input module, and an external device such as an actuator is connected to the output module. An input device such as a sensor senses the state of the control device and inputs the information to the input module, and an external device such as an actuator drives the control device in response to an output from the output module.

  In the above programmable controller, in the input module, an ON / OFF signal is input to the CPU module as input data using a switch, a sensor, or the like as an external contact. The power supply to the external device such as an actuator is cut off to drive the external device ON / OFF.

  It is necessary to filter and stabilize the input data including such contact ON / OFF signals so as not to be affected by noise due to the arrangement environment of the input / output module in the control operation of the programmable controller. For this reason, conventionally, a technique for filtering and determining input data has been proposed. For example, a technique has been proposed in which input data is sampled and the input data is filtered by determining the input data when the same sampling value continues for a specified number of times (see, for example, Patent Document 2).

However, in such a filtering method for determining input data, depending on the noise situation, it may take a considerably long time to determine the input data. For example, when the input data is sampled and the sampling value “1” continues five times (11111), when the input data is confirmed to be ON, the sampling values are (11110), (11110), (11110) depending on the influence of noise. ),..., (11111), the number of times of sampling until input data is determined increases, and input data determination often takes a long time.
Japanese Patent Laying-Open No. 2005-259079 JP 2007-156847 A

  The problem to be solved by the present invention is to enable early determination of input data in accordance with noise conditions.

  The input data filter method according to the present invention counts the number of sampling times when the input data is sampled and the same sampling value is obtained, and when the count value reaches a specified value, the input data is determined and the sampling interval is set. , At least one of the specified values can be arbitrarily set or changed.

  According to the present invention, the filter condition can be arbitrarily set and changed by setting or changing the sampling interval or the specified value according to the noise environment with indefinite state, so that the input data can be filtered so that it can be determined stably and early. it can.

  An input data filter device according to the present invention includes a sampling means for sampling input data, a filter counter for counting the number of samplings at which the same sampling value is obtained, and the input data is determined when the count value of the filter counter reaches a specified value. An arithmetic processing unit, wherein the arithmetic processing unit is capable of arbitrarily setting or changing at least one of the sampling interval of the input data and the specified value. It is.

  According to the present invention, input data can be filtered so that it can be determined stably and early.

  Hereinafter, an input data filtering method according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows an apparatus used to implement the input data filtering method of the embodiment. This input data filter device can be built in a programmable controller or the like, and is composed of, for example, a CPU, ROM, RAM, etc., a microcomputer including an interface, etc., and functionally a sampling circuit 10 and a filter counter 20. And an arithmetic processing unit 30.

  FIG. 2 shows the waveform of the input data. This input data indicates, for example, the voltage waveform of the contact ON / OFF signal of the programmable controller. The waveform portion having a high voltage value is a waveform portion indicating contact ON, for example, and is a waveform obtained by converting an analog signal waveform obtained by contact ON into a digital waveform suitable for processing by a microcomputer or the like. This input data is first input to the sampling circuit 10 and sampled for noise filtering. A sampling control signal for controlling the sampling operation to the sampling circuit 10 is given from the arithmetic processing unit 30. A sampling value of input data is given from the sampling circuit 10 to the arithmetic processing unit 30. The arithmetic processing unit 30 can input a sampling control signal that can set or change a sampling interval in a sampling operation of input data by the sampling circuit 10. The count operation of the filter counter 20 is controlled by a counter control signal from the arithmetic processing unit 30 as described later. A count value is input from the filter counter 20 to the arithmetic processing unit 30.

  In FIG. 2, a part of the contact ON signal waveform portion in the input data falls due to noise as a mere illustration. Of course, noise may not be superimposed, and more noise may be superimposed. Downward arrows S1 to S6 indicate sampling timing. The sampling interval is T. The input data sampling value at S1 is “0 (OFF)” for sampling at the contact OFF signal waveform portion (low level), and the input data sampling value at S2 is at the contact ON signal waveform portion (high level). It is “1 (ON)” for sampling. Similarly, the sampling value at S3 is “1 (ON)”, the sampling value at S4 is “1 (ON)”, the sampling value at S5 is “1 (ON)”, and the sampling value at S6 is “0 (OFF)”.

  The filter counter 20 counts up when the sampling value is “1 (ON)” and counts down when the sampling value is “0 (OFF)”. In the filter counter 20, all count values of 0 or less are “0”. Therefore, the count value of the filter counter 20 is counted down to “0” in S1, “+1” up to “1” in S2, “+1” up to “2” in S3, “2” up in S4, and “+1” up in S4. 3 ", S5 is incremented by +1 and is" 4 ", and S6 is decremented by -1 and is" 3 ".

  In the embodiment, the arithmetic processing unit 30 sets the count value “4” of the filter counter 20 as a specified value for determining the contact ON signal when the same sampling value is up-counted. When the number of times of sampling the same sampling value continuously is 4, the count value of the filter counter 20 becomes the specified value “4”. Further, even when the same sampling value is not continuously counted, the case where the count value of the filter counter 20 becomes the specified value “4” is included. This is because the filter counter 20 may count down due to the influence of noise in the middle of the contact ON signal waveform portion or otherwise. Thus, when the count value of the filter counter 20 reaches the specified value “4”, the input data is determined to be “1 (ON)” and the contact ON signal is determined.

  The above operation will be described with reference to the flowchart of FIG. First, at startup, step n0 is executed to reset both the internal input data stored in a memory (not shown) in the arithmetic processing unit 30 and the count value of the filter counter 20 to 0. The input data indicated by the waveform 2 is sampled by the sampling circuit 10 at S1, S2,. The sampling interval T of S1, S2,... Can be determined by the sampling control signal of the arithmetic processing unit 30. In step n2, the arithmetic processing unit 30 determines whether the sampling value in the sampling circuit 10 is zero.

  If it is determined in step n2 that the sampling value sampled in S1 is 0, the arithmetic processing unit 30 decrements the count value of the filter counter 20 by −1 in step n3. At this time, since the count value of the filter counter 20 is set to 0, in step n4, the arithmetic processing unit 30 determines that the count value of the filter counter 20 is −1 which is 0 or less. As a result, in step n5, the arithmetic processing unit 30 fixes the input data to 0 and sets the count value of the filter counter 20 to 0. Subsequently, the arithmetic processing unit 30 determines in step n6 that all input data processing has not been completed, returns to step n1, and performs input processing for the next input data.

  Then, at the next S2, the arithmetic processing unit 30 samples the input data at step n1, and when it is determined at step n2 that the sampling value is not 0, the count value of the filter counter 20 is incremented by +1 at step n7.

 In step n8 after this increment, it is determined that the count value of the filter counter 20 is “1” and has not reached the specified value (= 4). Then, the process proceeds to step n6 and the next sampling value is determined. Move on to input processing.

  In the next S3, S4, and S5, the arithmetic processing unit 30 repeats the above steps. As a result, in S5, the count value of the filter counter becomes the regulation “4”. As a result, in step n9, the internal input data is determined to be “1”, that is, the contact ON signal indicating that the contact is ON, the specified value is substituted into the filter counter 20, and the process proceeds to step n6.

  Subsequently, in the next S6, the process returns to step n1 and takes in the input data. In step n2, since the sampling value of the input data is 0, the filter counter is decremented by -1 in step n3. As a result, the count value of the filter counter becomes 3.

  As described above, according to the present embodiment, it is possible to set the sampling interval of the sampling timing and the specified value arbitrarily according to the noise situation, so that the input data can be determined early and stably. become able to.

  With reference to FIG. 4 to FIG. 6, the input data confirmation for the waveforms of various input data is specifically shown. FIG. 4 shows a filter example with a specified value “4” and a sampling interval “2 msec”. In FIG. 4, with respect to the input data waveform “... 011110...” Where “0” is the contact OFF signal and “1” is the contact ON signal, the sampling value is “… 000000 ...” and the count value of the filter counter 20 is “ ... 012343 ... ", and the value after filtering is" ... 000001 ... ". In this filter example, the determination of the contact ON signal takes 4 times the number of times of sampling when the sampling value “1111” of the input data waveform is continued 4 times × sampling interval 2 msec = 8 msec.

  In the above filter example, in an environment where an input is indefinite for 10 msec due to noise or the like, the input indefinite state is reflected, and therefore an incorrect result is output. An example of a filter that eliminates this is shown in FIG. In the filter example of FIG. 5, the specified value is “4” and the sampling interval is “3 msec”. In this filter example, it takes 4 sampling times × sampling interval 3 msec = 12 msec to determine the contact ON signal, so that it is possible to cope with input indefinite of 10 msec.

  On the other hand, changing the specified value of the filter counter 20 can also cope with the indefinite input. For example, as shown in FIG. 6, when the specified value is changed from “4” to “6”, the number of sampling times is 6 times × the sampling interval is 2 msec = 12 msec, and a filter exceeding 10 msec can be obtained.

  As described above, in the present embodiment, since the sampling timing for the input data in the sampling circuit 10 and the specified value of the filter counter 20 can be arbitrarily set, when the input state is indefinite due to the influence of noise, Filtering can be performed longer than the indefinite time, and input data can be determined stably at an early stage.

FIG. 1 is a block diagram of an input data filter device. FIG. 2 is a diagram showing a waveform of input data. FIG. 3 is a flowchart for determining input data. FIG. 4 is a diagram illustrating an example of a filter having a specified value “4” and a sampling interval “2 msec”. FIG. 5 is a diagram illustrating an example of a filter having a specified value “4” and a sampling interval “3 msec”. FIG. 6 is a diagram illustrating an example of a filter having a specified value “6” and a sampling interval “2 msec”.

Explanation of symbols

10 Sampling Circuit 20 Filter Counter 30 Arithmetic Processing Unit

Claims (2)

  Sampling the input data and counting the number of times that the same sampling value can be obtained. When the count value reaches the specified value, the input data is determined, and at least one of the sampling interval and the specified value is arbitrarily set. An input data filtering method that can be set or changed. Sampling means for sampling input data;
A filter counter that counts the number of times that the same sampling value is obtained;
An arithmetic processing unit for determining the input data when the count value of the filter counter reaches a specified value;
With
The input data filter device, wherein the arithmetic processing unit can arbitrarily set or change at least one of the sampling interval of the input data and the specified value.

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